1. Field of the Invention
The present invention concerns a method for data and signal transmission between terminal equipment via one or more switching stations in a distributed system. The invention also concerns a network fashioned for data and signal transmission according to such a method.
2. Description of the Prior Art
Medical-technical systems, in particular modern CT systems, have a number of connection lines between the individual sub-units, via which lines control signals for the activation of components of the system and digital data such as, for example, measurement data are transferred. Due to continuous development, CT systems require a flexible and scalable architecture that should strive to achieve a high reliability and a simple implementation of service tasks while also minimizing the cost expenditure for expansions.
Like the architecture of other medical-technical systems (for example in the field of magnetic resonance tomography), the architecture of currently used CT systems is based on the usage of a standard control network such as, for example, CAN (Controller Area Network) for the transmission of digital data with low speed. Furthermore, additional connection lines are used via which (normally logic) signals (such as, for example, control signals) are respectively transferred on the basis of a separate protocol and a separate specification, which signals must be updated frequently and very quickly during the system operation. This results in a number of connections with respectively different protocols, which makes a future improvement and expansion of such a system difficult.
A comparable problem also exists in other technical fields in which both hardware signals and data must be transferred, wherein a high quality of service (also designated as QoS (Quality of Service: measure for the reliability of the adherence to real time) in the following) must be achieved for a portion of the data or signals.
The previously used transmission technologies provide separate transmission of real hardware signals via hardware lines and data via field buses such as CAN or Profinet. Transmission technologies such as ATM (Asynchronous Transfer Mode), Sonet (Synchronous Optical Network) or Realtime Ethernet are known for the data transfer.
DE 691 16 538 T2 discloses a device for transmission of signaling data in an asynchronous network, in particular an ATM network, in order to be able to exchange data between synchronous and asynchronous networks. In the method of this publication the signaling data of the different channels from the synchronous network are detected and examined for state changes. Given each detected state change, an ATM cell is generated that comprises includes the appertaining channel number in its header and the new signaling is designated in the usage information field. This cell is then sent in the ATM network. In this manner data are transferred between terminal equipment lying outside of the ATM network via switching stations of the ATM network.